A ton of their data is going to come from apps and third party sites embedding scripts from Facebook. Hell, even social auth gives them a _ton_ of data. ("Oh, y

A ton of their data is going to come from apps and third party sites embedding scripts from Facebook. Hell, even social auth gives them a _ton_ of data. ("Oh, you recently used Facebook to sign into weddingplanner.com? Here come the wedding ads... and the related ads to all of your friends.")